abort() streams for segments that are no longer valid

lib/reader.js

@@ -50,8 +50,14 @@ function checknext(reader) {
       if (seq === state.nextSeq)
         state.nextSeq++;
 
-      if (object)
+      if (object) {
+        reader.watch[object.seq] = object.stream;
+        oncemore(object.stream).once('end', 'error', function() {
+          delete reader.watch[object.seq];
+        });
+
         state.active = reader.push(object);
+      }
 
       checknext(reader);
     });
@@ -122,7 +128,8 @@ function HlsStreamReader(src, options) {
     nextSeq:-1,
     active:false,
     fetching:null
-  }
+  };
+  this.watch = {}; // used to stop buffering on expired segments
 
   function getUpdateInterval(updated) {
     if (updated && self.index.segments.length)
@@ -140,6 +147,19 @@ function HlsStreamReader(src, options) {
         self.readState.nextSeq = self.index.startSeqNo(true);
       }
 
+      // check watched segments
+      for (var seq in self.watch) {
+        if (!self.index.isValidSeqNo(seq)) {
+          var stream = self.watch[seq];
+          delete self.watch[seq];
+
+          setTimeout(function () {
+            debug('aborting discontinued segment download');
+            if (!stream.ended && stream.abort) stream.abort();
+          }, self.index.target_duration * 1000);
+        }
+      }
+
       self.emit('index', self.index);
 
       if (self.index.variant)